Sistema Lacustre Ejidos de Xochimilco y San Gregorio Atlapulco. 02/02/04; Distrito Federal; 2,657 ha; 19°17'N 099°04'W. Protected area; World Heritage Site. A remaining ecosystem of the Mexico valley surrounded by the urban growth of Mexico City, consisting of seasonal freshwater lakes feeding from groundwater deposits, the site maintains today the cultural traditions of chinampas (crops in the wetlands). Vegetation is mainly of cattail Typha latifolia, bulrush Schoenoplectus americanus, the invasive water hyacinth Eichhornia crassipes, and trees such as Salix bonplandiana. The vulnerable Axolotl Salamander Ambystoma mexicanum inhabits the site, as well as other threatened or endemic species of reptiles, amphibians and birds. Water levels in the aquifers are being depleted, thus causing the terrain to sink and the soil to dry. Eutrophication, pollution, silting, salinization and invasive species are putting pressure on the site, not to mention the impacts of the surrounding urban environment. During weekends, thousands of tourist draw to the site for rides in typical boats (trajineras). A management plan is due to be ready in 2004. Ramsar site no. 1363. Most recent RIS information: 2004.